NASA-Led Study Pinpoints Areas of New York City Sinking, Rising

Photo: The land beneath the New York City area, including the borough of Queens, pictured here, is moving by fractions of inches each year. The motions are a legacy of the ice age and also due to human land usage. Credit: NASA/JPL-Caltech

Scientists using space-based radar found that land in New York City is sinking at varying rates from human and natural factors. A few spots are rising.

Parts of the New York City metropolitan area are sinking and rising at different rates due to factors ranging from land-use practices to long-lost glaciers, scientists have found. While the elevation changes seem small – fractions of inches per year – they can enhance or diminish local flood risk linked to sea level rise.

The new study was published Wednesday in Science Advances by a team of researchers from NASA’s Jet Propulsion Laboratory in Southern California and Rutgers University in New Jersey. The team analyzed upward and downward vertical land motion – also known as uplift and subsidence – across the metropolitan area from 2016 to 2023 using a remote sensing technique called interferometric synthetic aperture radar (InSAR). The technique combines two or more 3D observations of the same region to reveal surface motion or topography.

Much of the motion they observed occurred in areas where prior modifications to Earth’s surface – such as land reclamation and the construction of landfills – made the ground looser and more compressible beneath subsequent buildings.

Some of the motion is also caused by natural processes dating back thousands of years to the most recent ice age. About 24,000 years ago, a huge ice sheet spread across most of New England, and a wall of ice more than a mile high covered what is today Albany in upstate New York. Earth’s mantle, somewhat like a flexed mattress, has been slowly readjusting ever since. New York City, which sits on land that was raised just outside the edge of the ice sheet, is now sinking back down.

The scientists found that on average the metropolitan area subsided by about […]

Full article: www.jpl.nasa.gov